What happens in the lab after egg retrieval?

After egg retrieval, the laboratory starts to work. They have to first of all see how many of the oocytes that we get are mature, after that when they know how many matures, we have them injected and the next day we see if they were fertilized and we start a closest look at the develop of the embryo which will end on a day three or a day five (depending on the day that we decided to transfer) and myself, I’m a big fan of Day 5 but I know there’s many clinics all over the world that still transfer on day three and depending on that, we we start to look at the develop of the embryo and the biologists tell us how many cells, about their symmetry, the number – basically how they are developing – that’s how they gave us the quality of those embryos and then we decide if we have many embryos to transfer, we decide to pick up the best one the ones that have the best quality to transfer it first.

A lot of excitement happens in the lab. In fact through various videos this is one thing that I continuously try and aim to do is to educate our patients what exactly happens in the lab. And the journey is very exciting. As an embryologist I feel that I’m in one of the best professions that I could have ever asked to be in. Simply because not only are we helping patients, but the microbiology that we do under the microscope in the lab is absolutely fascinating.
So what happens in the lab? A lot happens. So let me run through the journey and this might be a very long-winded answer but I’ll try and summarise it.
Day zero is when we get the eggs collected. On day “zero” we put the eggs and sperm together. The same morning the male partner will produce a sperm sample. We will wash the sperm in the laboratory. If we’re using donor sperm then we’ll use frozen donor sperm to of course create embryos. We put the sperm and eggs together and achieve or try to achieve fertilization. The next day, which is called day 1 in embryology terms, we expect to see the eggs fertilized. Typically we expect 75 to 80 % of the eggs fertilized. Then we would observe the embryos the following day which is day 2. The embryo should be between two and five cells in development. The following day after day 3 which is 72 hours after insemination, we expect the embryo to be between 6 to 10 cells in development. And of course, at every stage the embryologist is assessing how these embryos are looking, how the cells are looking, how clean the embryos are, are they fragmented? And they should be keeping updating the patient on what they’re observing and so that’s day 3. And another two days later, which is five days later after the egg collection, the embryo should have reached what we call the blastocyst when the embryo should have over 120 or 140 cells in development. Continuously in that journey of five days there’s a lot of action happening in the lab, whereby your embryologist is continuously observing your embryos via or through all the technology that we have in the laboratory including such as time-lapse imaging which is giving so much information about your embryos. Helping the embryologist compare and select which embryo they like to transfer into the uterus, so the embryologist is that unsung hero behind the scenes who is working very hard after your egg collection, identifying so much information from your embryos in order to call you back and select the right embryo for transfer.